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arXiv · 2407.06659

The quantum metric of electrons with spin-momentum locking

Giacomo Sala·Maria Teresa Mercaldo·Klevis Domi·Stefano Gariglio·Mario Cuoco·Carmine Ortix·Andrea D. Caviglia
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Abstract

Quantum materials are characterized by electromagnetic responses intrinsically linked to the geometry and topology of electronic wavefunctions, encoded in the quantum metric and Berry curvature. Whereas Berry curvature-mediated transport effects have been identified in several magnetic and nonmagnetic systems, quantum metric-induced transport phenomena remain limited to topological antiferromagnets. Here we show that spin-momentum locking -- a general characteristic of the electronic states at surfaces and interfaces of spin-orbit coupled materials -- leads to a finite quantum metric. This metric activates a nonlinear in-plane magnetoresistance that we measure and electrically control in 111-oriented LaAlO$_3$/SrTiO$_3$ interfaces. These findings demonstrate the existence of quantum metric effects in a vast class of materials and enable previously unexplored strategies to design functionalities based on quantum geometry.

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Giacomo Sala, Maria Teresa Mercaldo, Klevis Domi, Stefano Gariglio, Mario Cuoco, Carmine Ortix, Andrea D. Caviglia. 2024-07-09. The quantum metric of electrons with spin-momentum locking. https://doi.org/10.1126/science.adq3255

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